[Bug libobjc/53944] New: Can't catch C++ exception in Objective C

[Bug libobjc/53944] New: Can't catch C++ exception in Objective C

[kostja.osipov at gmail dot com]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=53944

             Bug #: 53944
           Summary: Can't catch C++ exception in Objective C
    Classification: Unclassified
           Product: gcc
           Version: unknown
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: libobjc
        AssignedTo: unassigned@gcc.gnu.org
        ReportedBy: kostja.osipov@gmail.com


There is no way with GCC runtime to catch a C++ exception in Objective C code.
The catch-all clause doesn't work. 
At some point this limitation was documented, but later removed from the
manual.

Right now the code compiles, but fails to produce expected results.


kostja@atlas:~$ cat bar.cc 
extern "C" int bar()
{
    throw "exception";
}
kostja@atlas:~$ cat foo.m 
#include <stdio.h>
extern int bar();
int main()
{
    @try {
        bar();
    } @catch (...) {
        printf("caught\n");
    } @finally {
        printf("finally\n");
    }
}
kostja@atlas:~$ g++ -c -fexceptions bar.cc
kostja@atlas:~$ g++ -c -fexceptions -fobjc-exceptions  foo.m
kostja@atlas:~$ g++ foo.o bar.o -lobjc                      
kostja@atlas:~$ ./a.out 
terminate called after throwing an instance of 'char const*'
[1]    20822 abort (core dumped)  ./a.out

[Bug libobjc/53944] Can't catch C++ exception in Objective C

[kostja.osipov at gmail dot com]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=53944

Konstantin Osipov <kostja.osipov at gmail dot com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
               Host|                            |Linux atlas
                   |                            |3.2.0-26-generic #41-Ubuntu
                   |                            |SMP Thu Jun 14 17:49:24 UTC
                   |                            |2012 x86_64 x86_64 x86_64
                   |                            |GNU/Linux
            Version|unknown                     |4.6.3
           Severity|normal                      |major

[Bug libobjc/53944] Can't catch C++ exception in Objective C

[steven at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=53944

--- Comment #1 from Steven Bosscher <steven at gcc dot gnu.org> 2012-07-12 18:23:33 UTC ---
Try obj-c++

[Bug libobjc/53944] Can't catch C++ exception in Objective C

[kostja.osipov at gmail dot com]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=53944

--- Comment #2 from Konstantin Osipov <kostja.osipov at gmail dot com> ---
Objective C++ exception handling is broken in gcc completely, here's a small
example of trying to use C++ and Objective C exceptions together which
SEGFAULTs:



kostja@olah ~ % cat foo.mm 
#include <stdio.h>
#include <stdlib.h>

#import <objc/runtime.h>

@interface Object {
    Class isa;
}
+ (id) alloc;
- (id) init;
- (void) free;
@end

@implementation Object
+ (id) alloc
{
    return class_createInstance(self, 0);
}
- (id) init
{
    return self;
}
- (void) free
{
    object_dispose(self);
}
@end

@interface Frob: Object
@end

@implementation Frob: Object
@end

int proc() {
    @throw [[Frob alloc] init];
}

int foo()
{
    @try {
        return proc();
    }
    @catch (Frob *) {
        printf("Catch(Frob *)\n");
        return 0;
    }
    @catch (Object *) {
        printf("Catch(Object *)\n");
        return 0;
    }
    @catch (id) {
        printf("Catch(id)\n");
        return 0;
    }
    @catch (...) {
        printf("Catch(...)\n");
        return 0;
    }
}

int main(void)
{
    foo();
    return 0;
}
kostja@olah ~ % g++ -fobjc-exceptions foo.mm -lobjc
kostja@olah ~ % ./a.out 
zsh: segmentation fault (core dumped)  ./a.out